Racial discrimination and preterm birth subtype among a prospective cohort of nulliparous Black women in the United States, 2010-2013.

Racial discrimination has been associated with an increased risk of preterm birth (PTB) among Black women. Few studies have examined whether this association differs by clinical presentation of PTB. We examined the association between racial discrimination and PTB subtype using data from a 2010-2013 clinic-based prospective cohort study of nulliparous women among women who self-reported Black race. Lifetime racial discrimination was measured with the revised Experiences of Discrimination scale. We used inverse probability of exposure and post-stratification weights with the cumulative incidence function to estimate associations between racial discrimination and spontaneous PTB and indicated PTB within a competing risk framework. We estimated standard errors via bootstrapping. We stratified by education and age group to examine effect modification. Compared to none, racial discrimination in ≥3 situations was associated with 1.66 (95% CI, 0.72, 3.82) times the risk of spontaneous PTB and 0.37 (95% CI, 0.15, 0.93) times the risk of indicated PTB. Point estimates between racial discrimination and spontaneous PTB were strongest among women with some college education and ≥20 year-olds. Future studies should consider clinical subtype in assessments of the association between racism and preterm birth and include in the study design late prenatal care initiators.